Monitoring system for concrete pilings and method of installation

ABSTRACT

A system for tracking and monitoring data related to the manufacture, installation and/or life cycle of concrete structures, such as pilings, as well as related system components and methods for tracking, storing and accessing such data is provided. The system utilizes one or more embeddable antenna assemblies as well as sensor packages that are installed in the concrete structure form before casting. The antenna(s) provide wireless communication of the data from the structure. On board memory is also provided to store structure related data with the structure. A system for tracking a pile during driving is also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. Ser. No. 11/188,492, filed Jul.25, 2005 which claims the benefit of U.S. provisional patent 60/685,807,filed May 31, 2005; U.S. provisional patent 60/642,585, filed Jan. 10,2005; and U.S. provisional patent 60/590,955, filed Jul. 23, 2004, allof which are incorporated herein by reference as if fully set forth.

BACKGROUND

The invention relates to a monitoring system for long term monitoring ofconcrete pilings and structures, as well as a means of installing andconnecting such systems to pilings and structures that have gauges andsensors pre-cast therein.

There is currently no efficient way to communicate information from aconcrete structure such as a pile or span, in order to determineconditions related to or generated by installation of such structures.Currently, with concrete structures, such as pilings, that are to bemonitored, only approximately one in ten are actually monitored for loadbearing and other stress/strain related data due to the significanteffort required to manually attach strain gauge/accelerometer monitoringdevices to monitor the forces and velocities in the pile duringinstallation. As pilings are generally positioned using choker cablesthat wrap around the structure that are then lifted by a crane, it isnot possible to have anything located on the outside of the piling dueto the high risk of it being damaged or cut off by the choker cableduring positioning. Currently, after the piling is positioned fordriving, the required gauges and sensors are manually attached byclimbing to the desired position and attaching them to the standingpile. This is labor intensive, time consuming, costly, and also imposesa safety risk to the installer. As such, only limited monitoring isgenerally undertaken, resulting in higher design safety factors beingrequired for the structure. A means of performing wireless monitoring atthe time of driving would have significant value in reducing the costand time associated with the testing process, thereby enabling moretesting. But there are numerous technical obstacles in doing so,including the wireless transmission of sensor data from the pile.

A basic problem with placing an RF antenna up against, or embedded inconcrete is that its performance will be greatly degraded due to theconcrete's large dielectric component that varies with the age of theconcrete. This presents a very difficult, challenging applicationenvironment. With air having a dielectric constant of 1.0, and water 80,concrete varies anywhere from 20 (fresh) to 6 (fully cured after acouple of months depending on water content). The concrete structures inthis application are being used about 28 days after cast or sooner, andsubsequently were found to have a dielectric constant of about 9.0.

The relatively high dielectric of the concrete placed in close proximityto the RF antenna causes most of the energy emitted from the (nowdetuned) antenna to be pulled from the antenna and into the concrete.Whatever remaining RF energy coupled to free-air is severely attenuatedwith distorted and/or erratic patterns, as typical antenna designs aremodeled to operate in a free-air environment.

Additionally, after a structural element, such as a pile, is set, nofurther data is gathered for analysis which could be used for monitoringthe long term stability and structural soundness of the structuralelement in view of cyclic loading and exposure to harsh environmentsthat could cause the structural element to degrade over time, resultingin structural failure.

It would be desirable to provide a more efficient and cost effectivemethod and system for monitoring such concrete structures through theentire useful life of the structure. More preferably, it would bedesirable to provide a system that can be easily installed during thecasting and manufacturing process which allows monitoring to be done insuch a cost effective manner so that all of the concrete structures in agiven application, and in particular pilings for buildings, bridges androadbeds, can be monitored in order to allow for more efficient designsto be utilized without compromising the safety or reliability of theoverall structure. Additionally, it would be desirable to provide asystem for life-cycle monitoring of such concrete structures, includingall concrete structural elements regardless of whether, such as in thecase of a piling, the top is cut off after installation. It would alsobe desirable to provide a means of monitoring embedded gauges regardlessof the final state of the structure.

SUMMARY

The invention provides a system for tracking and monitoring data relatedto the manufacture, installation and/or life cycle of concretestructures, such as pilings, as well as related system components andmethods for tracking, storing and accessing such data.

In one aspect of the invention, a permanent, embedded antenna with areflector is provided that does not protrude from the surface of thestructure during fabrication and transport. The antenna is insertedflush to a sidewall of the concrete structure, and extends only to alimited extent into the structure from the outside surface, so thatstructural integrity is not compromised. Additionally, the antenna isspaced away from the internal steel skeleton of the structure to preventmoisture ingress and the associated structural integrity loss.

The antenna mounting/design must withstand a repetitive, high-shockapplication environment, characterized by a high number of hammer blowswith g-forces of up to about +/−1000 g's. For example, as seen duringdriving of reinforced concrete pilings.

Additionally, the antenna is subject to an outdoor operating environmentincluding exposure to moisture, and does not hold or retain moisture, asthis would impair or disable antenna performance.

The antenna of the invention is permanently embedded in the structure,and subsequently disposable and of low cost.

According to another aspect of the invention, an antenna arrangement isprovided that is embedded below the surface of the concrete structureduring fabrication. The antenna arrangement includes an actuator thatmoves the antenna from a first, stowed position, to a second, extendedposition in which it protrudes from the surface of the concrete surface.The actuator can be manual or can be triggered by a certain load or anoriented shock wave transmitted through the concrete structure, such asthe first blow(s) of a pile driving hammer, or through a control commandor other electrical signal.

The present invention also provides an economical and fast method ofinstalling sensors and gauges in an easy and repeatable manner in apiling form prior to casting using a U-bar suspension assembly. TheU-bar suspension assembly provides for vertical placement of thesensor/gauge package reducing the possibility of damage to thesensor/electronics during casting, and preferably automatically centersthe sensor/gauge package in the piling form prior to casting, ensuringthe accuracy of the sensor reading.

The invention also provides history tracking and recording memory toallow tracking of piling information throughout installation of thepiling, which can also be used to provide active feedback to workersduring installation.

The present invention also provides a method of life-cycle monitoringfor pilings in addition to other concrete structural elements. Themethod includes inserting one or more sensor/gauge packages betweenstrands in a piling form to position sensors in a piling core area.These can be, for example, strain gauges, accelerometers, core pressure,temperature and/or moisture sensors and the like. The piling is thencast, encapsulating the sensors. Preferably, a radio/antenna assembly ispositioned in the form and pre-cast into the piling as well, with atleast the antenna being exposed on a side of the piling near the top.The piling is driven at the construction site, and data is obtained inreal time from the sensor/gauge package(s) during driving. This data istransmitted to a control/monitoring system to allow for real time reviewand analysis of the drive data. After driving, the piling is retrofittedwith a networked monitoring node that is connected/interfaced to theexisting sensor/gauge package(s). Unique addressing information of agiven piling is retained, preferably by logically linking a sensorpackage address ID. These nodes (and potentially nodes from othersensors in the complete structure) are then connected/networked to anexternal gateway to allow for life cycle monitoring of some or all ofthe complete structure.

BRIEF DESCRIPTION OF THE DRAWING(S)

The foregoing summary, as well as the following detailed description ofthe preferred embodiments of the invention, will be better understoodwhen read in conjunction with the appended drawings. For the purpose ofillustrating the invention, there are shown in the drawings embodimentswhich are presently preferred. It should be understood, however, thatthe invention is not limited to the precise arrangements shown.

FIG. 1 is a perspective view showing strands in a piling form prior tocasting concrete into the form in order to form the piling.

FIG. 2 is an enlarged perspective view similar to FIG. 1

FIG. 3 is a perspective view showing the piling form after the concretehas been cast into the form.

FIG. 4 is an exploded view of a first embodiment of an antenna assemblyin accordance with a first embodiment of the present invention.

FIG. 5 is a cross-sectional view of the antenna of FIG. 4 shown embeddedin a side of a concrete structure, such as a piling.

FIG. 6 is a perspective view showing the location of opposing antennaslocated on the top of a pile.

FIG. 7 is a side view of a deployable antenna assembly that is flushmounted to the surface of a concrete structure,

FIG. 8 is a perspective view of the antenna of FIG. 7.

FIG. 9 is a perspective view of an alternate embodiment of a sitedeployable antenna according to the invention.

FIG. 10 is a perspective view, partially disassembled, of a reflectorused to form another antenna assembly according to the invention.

FIG. 11 is a perspective view showing a second reflector assembly,partially disassembled, in accordance with the present invention.

FIG. 12 is an exploded view of an antenna housing and reflector assemblywith an attached and externally exposed electronics module housing.

FIG. 13 is an enlarged cross-sectional view of a polymeric plug used forsealing the antenna tube and housing shown in FIG. 12.

FIG. 14 is a front elevational view of a first type of end cap for theantenna reflector assembly shown in FIG. 12.

FIG. 15 is a front elevational view of a second end cap for the antennareflector assembly shown in FIG. 12.

FIG. 16 is a perspective view of another antenna assembly according tothe invention, similar to that shown in FIG. 12, without the electronicsmodule housing.

FIG. 17 is a perspective view of an antenna assembly similar to thatshown in FIG. 12, with a release gasket located around the electronicsmodule housing cover.

FIG. 18 is a rear perspective view of the antenna assembly shown in FIG.17.

FIG. 19 is a cross sectional view through a piling form showing theopposite positioning of antenna assemblies according to the invention inthe piling form.

FIG. 20 is a cross-sectional view through the piling form showing thestrands and a U-Bar suspension assembly according to the invention forvertical mounting of gauges in the piling.

FIG. 21 is an exploded perspective view of the U-Bar suspensionassembly.

FIG. 22 is a side elevational view, shown partially schematically, ofthe assembled U-Bar suspension assembly shown with a strain gauge, anaccelerometer and an electronics module mounted thereon.

FIG. 23 is a side elevational view similar to FIG. 22 of anotherembodiment of a U-Bar suspension assembly with the strain gauge,accelerometer and electronics module.

FIG. 24 is a perspective view of the electronics and sensor mounting onthe center section of the U-bar suspension assembly of FIG. 23.

FIG. 25 is a rear perspective view showing the sensor mounting relativeto the U-bar suspension assembly of FIG. 24.

FIG. 26 is a cross-sectional view of a water tight housing for theaccelerometer.

FIG. 27 is a schematic view of a pile showing the connection between thetop and tip sensor/gauge packages and the radio/electronics compartment.

FIG. 28 is a schematic view of a pile similar to FIG. 27, in which thepile includes a wire reservoir and guide tube to allow for connection tothe embedded tip gauges for pilings which have the top cut off afterdriving.

FIG. 29 is a cross-sectional view through the piling taken along line29-29 in FIG. 28.

FIG. 30 is a schematic view of the pile sensor and antenna arrangementof FIG. 28 shown without the pile.

FIG. 31 is a schematic view of a pile showing the common data backboneand an intra-pile transmission system.

FIG. 32 is a perspective view of a driven piling top having the radioelectronics being replaced with a network node module.

FIG. 33 is a perspective view of a piling with the top cut off, showingthe connection with a network node module.

FIGS. 34A-34C are a flow chart showing the life cycle monitoring systemin accordance with the present invention.

FIG. 35 is a perspective view of the a concrete cap cast over aplurality of piling tops that have monitoring sensors that are connectedtogether to a node for connection to additional members of the structureand/or telemetry uplink for data acquisition and monitoring.

FIG. 36 is a perspective view of a system for tracking a penetrationdepth of a piling according to the invention.

FIG. 37 is a perspective view of an alternate system for tracking apenetration depth of a piling.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

Certain terminology is used in the following description for convenienceonly and is not considered limiting. The words “lower”, “upper”, “left”and “right” designate directions in the drawings to which reference ismade. As used herein, the recitation of “at least one of A, B and C”means any one of A, B or C or any combination thereof, where A, B and Crepresent the noted features of the invention. Additionally, the terms“a” and “one” are defined as including one or more of the referenceditem unless specifically noted.

Referring to FIG. 1, strands 12 for a piling 10 are shown positioned ina piling form 14 prior to casting concrete in the form 14 in order toform the piling. Sensors 16 and an antenna assembly 18 for transmittingdata from the piling during or after installation are shown connected toor suspended from or above the strands 12, preferably using cable tiesor similar holding devices. Sensors and antennas are preferably used formonitoring of the pilings using a direct wireless data transfer of databeing gathered by the sensors embedded in the pilings as described indetail below, for installation and/or lifetime monitoring of the pilingas well as also possibly for storing pile data.

FIG. 2 shows an enlarged view of a preferred antenna/radio assembly 60temporarily located lying on top of the pile strands 12, which willfloat in the concrete that is cast in the form so that a top surface ofthe antenna/radio assembly 60 is located on a surface of the pile.Additionally, the sensors 16 are attached to a preferred suspensionassembly as explained in further detail below in order to position thesensors 16 between the piling strands 12.

FIG. 3 shows the piling 10 cast in the form 14 after the concrete hasbeen poured. The surface of the antenna 18 remains exposed for signaltransmission before, during and/or after the pile drive. Also, the cover64 of the antenna/radio assembly 60 remains exposed. It is also possibleto remove the antenna 18 and incorporate the antenna into the cover 64of the electronics module housing 61, as explained in detail below.

A first embodiment of an antenna assembly 18 according to the presentinvention is shown in FIGS. 4 and 5. The antenna assembly 18 is flushmounted in the side of a concrete structure, such as the piling 10,shown in FIG. 3, during fabrication. It is necessary to ensure that theantenna is decoupled from the surrounding concrete of the piling 10.This is achieved by providing a corner reflector 24, preferably made ofmetal, such as steel or aluminum, or may be made from plastic with anelectrically conductive coating. While prior corner antennas have beenused in other applications to provide gain, in the present case it isused in an unconventional manner to provide isolation of the antennafrom the surrounding concrete structure 12 in which it is embedded. In atypical corner reflector application, the reflector is placed a ½ wavelength away from the antenna such that the reflected wave will add inphase and provide gain. Due to the depth restriction in the presentapplication based on the structural reinforcements in the concrete, themetal surface of the corner reflector 24 is only placed far enough fromthe antenna so as to minimize the detuning effects to the antenna(resulting in impedance mismatch losses), and not too far away so as tominimize the destructive interference caused by the reflected wave. Inone application, a distance of 2.1 inches is preferred for a referencewavelength of 916 MHz, providing a spacing of approximately ⅙ of a wave.

In another embodiment of the invention with a shorter wavelength/higherfrequency (for example, 2.4 GHz), a smaller overall geometry of theembedded antenna assembly is provided with only a spacing of about 1inch being necessary.

Still with reference to FIGS. 4 and 5, an antenna 26 is held in positionrelative to the back metalized reflector with an open cell foam block 28or other similar non-moisture absorbing or holding spacer. Preferably, acover plate 30 made of an RF transparent material at the frequency ofinterest is installed over the antenna 26. Preferably, the cover isflush with the surface of the concrete structure 12, as shown in FIG. 3.A grommet 31 is preferably placed around the wire or coax cableextending from the antenna 26. The entire assembly 18 is preferablyassembled in a water tight manner.

Referring to FIG. 6, a preferred placement of the antenna 18 on opposingfaces at the top end of the pile 10 is shown. Preferably, the antennaassembly 18 is located 2 d down from the top where d is a width of thepile 10. The sensors 16 are preferably also placed at a location 2 dfrom the top and additional tip sensors are placed 2 d from the piletip, as noted in detail below. However, the sensors are located in themiddle/core of the pile cross-section.

Referring to FIGS. 7 and 8, in another embodiment of the invention, asingle (or multiple) retractable, spring-loaded antenna assemblies 50are provided. The antenna 52 remains flush with the pile surface duringmanufacturing and transportation of the pile. The antenna assembly(s) 50have the antenna 52 extend to a deployed position only after either asignificant vertical blow, such as from an actual pile hammer blow, orafter a control command is received and actuates a solenoid drivenrelease. An electrically conductive ground plane 54, preferably made ofmetal or an electrically conductive material coated on an insulatingsubstrate, is mounted flush to the surface of the concrete structure,and in effect sits on the surface like the cover 30 until the antenna isdeployed, and thereupon acts as a part of the antenna structure. Thelength of the antenna 52 is preferably ¼λ, and the ground plane 54 hasdimensions of approximately λ/2 and could be round or square with adiameter or side length of approximately λ/2. While this arrangement ispreferred, other arrangements are possible.

Alternatively, or in addition to the remote release, a manual pushbutton override 55 is provided in case the automatic extension attemptsfor the antenna assembly 50 fail. This can be in the form of a smallopening located in the ground plane 54 to allow a user to insert a rodor pin and release a catch holding the antenna 52 in the stowedposition.

Once the proper magnitude blow or control command is received, theantenna(s) 52 extends orthogonal from the concrete surface. This iseasily achieved through a hinge-mounted antenna 52, as shown in FIG. 8.The blow or control activated solenoid or plunger releases a catch, andthe antenna rotates outwardly driven by the force of a circumferentialforce coil spring or a compression spring (not shown). Alternatively, asshown in FIG. 9, the assembly 56 can include an antenna 57 located in anelectrically non-conductive sleeve 58 that extends generallyorthogonally to the surface of the electrically conductive ground plane54 a located on the surface of the concrete structure, and uponactivation of a release catch, either through a detected blow or througha control signal as described above, the catch is released resulting inthe antenna 57 springing outwardly from the sleeve 58 to an extendedposition above the ground plane 54 a.

If an antenna(s) hits grade (water or ground) during installation,internal sensing circuitry will switch transmission of data to anabove-grade antenna or internal transceiver as in the case of a splicedpile or allow direct connection via a jack to export data, as discussedin detail below.

Referring to FIGS. 10 and 11, two additional alternative embodiments ofantenna assemblies 80, 90 are shown. These antenna assemblies areconstructed in a very cost effective manner, and use of a low loss andlow dielectric material plug 82, 92 having a thickness of λ/4 andpreferably a diameter greater than or equal to λ/2. The plug can be madeof plastic or any suitable material meeting the requirements set forthabove, and is preferably cylindrical (FIG. 10), hemispherical orparabolic (FIG. 11). The sides and bottom are covered with anelectrically conductive coating 84, 94, such as metalized foil or anyother suitable material. An externally sealed center opening 85, 95 isprovided through which the center wire 86, 96 of a coax cable 88, 98extends to a length of λ/4. The ground braid of the cable 88, 98 issoldered or otherwise connected to the electrically conductive coating84, 94 in the area of the center opening 86, 96 where it extends throughthe bottom of the plug 82, 92. The top surface of the plug 82, 92 actsas a cover and is installed flush with the surface of the concretestructure during fabrication in order to provide a low cost antenna.

Referring to FIGS. 12 through 15, a preferred embodiment of the upperantenna/radio assembly 60 is shown in detail. The antenna assembly 60preferably includes a reflector assembly 65 having a reflector body 66formed from a bent-up metallic sheet, preferably formed into a V-shape,with end caps 68 and 70, shown in FIGS. 14 and 15, attached to the endsthereof. Preferably, the reflector assembly 65 is formed from metallicmaterials, such as aluminum or stainless steel. However, other suitablemetallic materials may be utilized or a polymeric material having ametallic coating would also be suitable. A protective cover 72 formed ofan RF transparent material at the desired frequency is provided. Thecover 72 is required during manufacture of the piling in order to keepconcrete out of the antenna assembly 60 during casting, and can beremoved after the concrete is set, if desired. In a preferredembodiment, this is formed of heavy card stock/cardboard or a polymericmaterial having a thickness of above 0.02 inches and can be adhered,taped or otherwise sealed onto the reflector assembly 65.

The antenna assembly 60 further includes the housing 61 for wiring andelectronic components associated with the antenna 76 as well as a radiomodule for transmission of a data signal. The antenna 76 is preferablylocated within an antenna tube 78 formed of a polymeric material, suchas PVC, that is connected in a water tight manner to the housing 61,preferably using a coupling 69 that extends from the housing 61 and aplug 79 inserted from inside the housing 61 into the coupling 69 andaround the antenna base, shown in detail in FIG. 13. The plug 79 ispreferably sealed or glued within the housing 61, as indicated at 81.The reflector assembly 65 is installed over the antenna tube 78 suchthat the first end cap 68 is up against the housing 61. A tube end cap83 is used to seal the end of the antenna tube 78 after the antenna 76is installed. Water tight connectors 91 can be inserted into opening(s)in the sides of the housing 61 in order to provide water tight entry andexit points for wiring, cables or the like used for data signaltransmission and/or power transmission to the various elements of thesensing system located within the piling 10. Additionally, a buoyancycompensation plate 87 is preferably connected to the bottom of thehousing 61 with, for example rivets, to the provided flanges or by anyother suitable connection, such as clips, adhesive, cable ties or thelike. The buoyancy compensation plate 87 is sized so that a sufficientamount of concrete is located thereon to counteract the buoyancy of theantenna assembly 60 so that it is maintained in a floating positionabove the piling strands with the cover 72 generally flush with thepiling surface.

Preferably the housing 61, the coupling 69, the plug 79, the antennatube 78, the anti-buoyancy plate 87 and the end cap 83 are all made ofPVC or a similar polymeric material and can be assembled and adheredtogether in a simple and efficient manner. The cover 72 for thereflector assembly 65 is preferably positioned within the piling form 14so that it is maintained along and forms a portion of the outer surfaceof the piling. Additionally, preferably an access cover 64 is providedfor the housing 61, and is also located at the surface of the piling inorder to allow access to the wiring, cables, battery, diagnosticsupport, and/or electronic components located therein after the pilingis formed.

Referring to FIG. 16, the reflector assembly 89 for the second antennaassembly 62 is shown and includes the cover 72 as well as the preferablyV-shaped reflector body 66. Two reflector end caps 70 are utilized toclose off the ends of the reflector assembly 89 and the antenna 76within the antenna tube 78 are installed therein. Once the antenna isinstalled within the tube 78, the ends are sealed in a water tightmanner utilizing tube end caps 83 or similar type end caps so that onlythe antenna cable extends out from one end of the reflector assembly 89in order to form the second antenna assembly 62.

Referring to FIGS. 17 and 18, the preferred antenna/radio assembly 60 isshown with an improvement for installation. In order to allow removal ofthe cover 64, a foam or rubber sleeve 63 is installed around the top ofthe housing 61, as shown in FIG. 17, and extends up past the lip of thecover 64. This prevents the concrete that is used to form the pile 10from locking the cover 64 in position, and the sleeve 63 is preferablyremoved after the concrete is set to provide an air gap to allow removalof the cover 64. Alternatively, the sleeve 63 can remain and act as aseal to prevent the ingress and settling of moisture.

A plurality of individually switchable and uniquely identified antennasare preferably embedded in the concrete piling structure, preferablyincluding one antenna assembly 60 with an attached radio module in thehousing 61, and possibly one or more of the antenna assemblies 62 orother types of the antenna assemblies identified above. The antennas areenabled, preferably automatically, in a round robin fashion to identifywith a receiving system which antenna position provides the best signalstrength and subsequently the highest data bandwidth capabilities basedon the physical position of the receiving system. Only this antenna(position) is then selected and enabled for all subsequent datacorrespondence. In order to optimize performance, power is not routed tothe unused antenna positions during data acquisition. It is possiblethat if during data acquisition, the signal from the selected antenna islost, the system can try to automatically establish contact with one ofthe remaining antennas.

The antenna selection criteria is preferably based on a combination ofthe received signal strength indicator signal (RSSI), link quality, andcalculated test signal transmission bandwidth. The specific protocolused to select and enable the antenna can be selected based on theparticular systems utilized and application. However, generally only theantenna with the best transmission performance is selected for use andpowered. Once selected, full system power is sent to the selectedantenna to extend the system battery life while providing the bestsignal strength and the highest bandwidth. Also, because the antennastructure is exposed on the face of the piling, the use of multipleantennas provides redundancy and recovery options in the event of damageto one antenna.

Referring now to FIG. 19, antenna assemblies 60, 62 are shown positionedwithin the piling form 14. The upper antenna assembly 60 is preferablyfloating in the concrete above the strands 12 to prevent any sources ofwater ingress from reaching the strand skeleton after manufacture. Thelower antenna 62 may be placed at the bottom of the form flush with thebottom surface, and is held in position by the weight of the concretebeing cast. Other types of the antenna assemblies described above couldalso be utilized. It is also possible to locate the antenna assemblieson opposing sidewalls of the piling form 14.

One problem encountered with the installation of the sensors shown inFIGS. 1-3 is that during pouring of the concrete and subsequent settlingusing a vibrator or other means, the potential for damage to the sensorswas increased due to the horizontal mounting of the sensors on orbetween the strands 12, presenting a large profile through and overwhich concrete must be poured and/or tamped.

As shown in FIG. 20, in accordance with the present invention a U-Barsuspension assembly 120, 120′ is preferably installed generallyvertically in the piling form 14 in order to facilitate fast, accurateand repeatable positioning of the sensors located thereon. Preferably,this includes an accelerometer 122 and a strain gauge 124, which must bepositioned cross-sectionally within the pile core. The U-Bar suspensionassembly 120, 120′ is preferably spring loaded and allows repeatablepositioning of the sensors within a center of the core area of thepiling form 14 without the need for hand measurements while maintainingthe accelerometer in a position orthogonal to the pile length in orderto allow accurate acceleration measurements during subsequent driving ofthe pile, and also maintaining the strain gauge in a position parallelto a longitudinal axis of the pile to ensure accurate strainmeasurements.

Referring to FIGS. 21 and 22, a first embodiment of the U-Bar suspensionassembly 120 will be described in detail. The U-Bar suspension assembly120 includes upper and lower U-shaped frames 126, 128. The legs of thelower U-shaped frame 128 are slidable within the legs of the upperU-shaped frame 126. Springs 130 are located within the legs of the upperU-shaped frame 126 and bias the upper U-shaped frame 126 away from thelower U-shaped frame 128. A combined upper shield/hook 132 and one ormore lower hooks 134 are each attached to the base of the upper andlower U-shaped frames 126, 128, respectively. The shield/hook 132 andhook(s) 134 can be made of any suitable material that avoids galvaniccorrosion and may have any suitable shape which is sufficient to engagethe strands 12 when the U-Bar assembly 120 is installed in a generallyvertical orientation in the piling form 14, as shown in FIG. 22. Theupper shield/hook 132 is preferably wide enough to protect thegauge/sensor arrangement from damage during casting of the concrete andsubsequent vibratory settling/tamping.

For installation, the U-Bar suspension assembly 120 can be insertedbetween the strands 12 with the lower hook(s) 134 engaged on a lowerstrand 12. The U-Bar suspension assembly 120 is then compressed bypressing the upper U-frame downwardly against the force of springs 130so that the legs of the lower U-frame 128 are telescopically receivedwithin the legs of the upper U-frame 126. Upon releasing force on theupper U-frame 126, the upper and lower U-frames 126, 128 are biased awayfrom one another by the springs 130 and the hook portion of the uppershield/hook 132 can engage against the underside of an upper strand 12within the piling form 14.

Referring again to FIGS. 21 and 22, the U-bar suspension assembly 120further includes a carrier sled 136 connected thereto. The carrier sled136 preferably includes guide flanges 138 which contact the legs of theupper and lower U-shaped frames 126, 128 in order to position themounting platform. An upper portion of the carrier sled 136 preferablyincludes an extension 137 that is bent in a generally U-shape in orderto hold and protect an electronics module 159, shown in FIG. 22.Alternatively, this can be a separate piece or part of the electronicsmodule housing.

Centering springs 140 are preferably provided and have a first endconnected to the upper U-shaped frame 126 and the lower U-shaped frame128, respectively. The second ends of the centering springs 140 areconnected to brackets 141 on the upper and lower sides of the carriersled 136 and bias the carrier sled 136 to a generally centered positionregardless of the distance between the hooks 132, 134 in the installedposition on the strands 12. The brackets 141 are spaced so that thegauge/sensor assembly will be approximately centered in the piling,preferably by equal spacing “a” from a center line of the mountingposition of the sensor/gauge assembly. As shown in FIG. 22, the forcevectors for the centering springs 140 have primary Y force components.However, based on the mounting arrangement, there is also thepossibility of providing an X force component that holds the carriersled 136 against the U-shaped frame members 126, 128. The centeringsprings 140 ensure that the carrier sled 136 is in a repeatable,centered position upon installation without the need for an installer toreach down between the strands and measure and adjust the position ofthe carrier sled 136. The centering springs 140 have a lower springconstant than the springs 130. Once the suspension assembly is inposition, the carrier sled 136 is clamped and/or held in the centeredposition using wire ties, hose clamps, thumb screws or other similardevices. This prevents concrete and/or the subsequent vibration/settlingfrom moving the carrier sled 136 from the spring equilibrium position.

Alternatively, other spring arrangements can be utilized, or thecentering springs 140 can be omitted and the mounting platform can beinstalled on the U-Bar suspension assembly 120 by cable ties, bent wire,or other suitable fasteners, such as those mentioned above.

A mounting plate 139 is connected to the carrier sled 136, preferablywith cable ties, wire ties or the like. The mounting plate 139 registersin position on the carrier sled 136, preferably using alignment holes,tabs or other similar measures. The accelerometer assembly 122 ispreferably attached to the mounting plate 139 with cable ties or othersuitable types of connectors, such as mechanical fasteners, epoxy or anyother suitable means. Alternatively, the mounting plate 139 can beomitted and its mounting features incorporated onto the carrier sled136.

Referring to FIGS. 23 and 24, a second embodiment of the U-barsuspension assembly 120′ is shown. The second embodiment 120′ is similarto the embodiment 120, except the need for the springs 130 has beeneliminated, and the mounting plate 139 is eliminated with its functionbeing incorporated in one piece with the carrier sled 136′. In the U-barsuspension assembly 120′, the U-frames 126, 128 are slidable togetherand apart in the same manner as discussed above. However, the lowerU-frame 128 includes a series of holes in the legs which can be alignedwith holes in the legs of the upper U-frame 126 and pinned togetherusing pins 133, which can be pins, bolts, rivets or any other suitablefasteners. The U-frames 126, 128 are adjusted for the particular strand12 spacing for a pile 10 to be formed. The pins 133 are then installed.The bottom hooks 134′ are formed of spring steel or another suitableresilient material. During installation, the U-bar suspension assembly120′ is inserted between the strands 12 and the lower spring hooks 134′engage a lower strand. The spring hooks 134′ elastically deflect inorder to allow the upper hook 132 to be inserted under the desired upperstrand 12 in the form 14, and then resiliently bias the upper hook 132into engagement with the upper strand. The strands themselves alsoprovide some resiliency and can be sprung apart to allow installation ofthe U-bar suspension assembly. The holes in the legs of the lowerU-frame 128 can be positioned in the appropriate locations for knownstandard strand locations for a number of known piling sizes. Thecarrier sled 136′ with the attached gauges and sensors can be connectedto the U-frames 126, 128 in a centered location using cable ties,clamps, rivets or any other suitable fasteners.

Preferably, the accelerometer assembly 122 preferably includes a housing142, as shown in detail in FIG. 26, which maintains a water tight cavityin which the physical accelerometer device is held. The housing 142 ispreferably made of a top housing part 144 and a bottom housing part 146which define a cavity 148 for the physical accelerometer device therein.An O-ring 150 is located in a circumferential groove in the upperhousing part 144. Once the physical accelerometer device is installedwithin the cavity 148, the top and bottom housing parts 144, 146 areassembled, preferably using an adhesive to hold the parts 144, 146together. The top and bottom housing parts 144, 146 for theaccelerometer housing 142 are preferably made from a polymeric material,such as a low cost polycarbonate. A channel 152 is preferably formedaround the periphery of the housing 142 which allows for the physicalalignment and mounting on the carrier sled 136′ or the mounting plate139, if provided separately, using a cable tie received within thechannel 152, as shown in FIGS. 22-25.

As shown in FIG. 21, preferably an opening 154 is located in themounting plate 139 in which the accelerometer housing 142 is secured.The opening 154 has V-shaped sidewalls for registration/alignment sothat the accelerometer housing 142 is held firmly and accurately inposition by the peripheral circumferential edges of the housing 142being in registration with V-shaped walls. Slots are preferably providedin the mounting plate 139 for the cable ties to extend through forattachment of the accelerometer. The opening 154 also allows theconcrete used for the piling to form around the accelerometer assembly122 in its housing 142 in order to ensure that accurate data iscollected by the accelerometer. Alternatively, as shown in FIG. 24, thesame type of opening 154′ is located directly in the carrier sled 136′to allow mounting of the accelerometer assembly 122 in the same manner.

The strain gauge 124 is preferably also installed on the carrier sled136′ or the mounting plate 139, if provided as a separate part forpre-assembly, using cable ties. As shown in FIG. 21, an opening 156 ispreferably provided through the mounting plate 139 in the area of thestrain gauge 124 so that the concrete used for the piling can be formedaround the strain gauge 124 in order to ensure that accurate data iscollected by the strain gauge 124. A similar opening 156′ is alsoprovided directly in the carrier sled 136′ in the embodiment shown inFIGS. 23 and 24.

An electronics module 159 for the strain gauge 124 and the accelerometeris also preferably attached to the carrier sled 136, 136′, as shown inFIGS. 22 and 24. Alternatively, this can be positioned elsewhere in thepiling form 14.

The mounting plate 139 is preferably formed from a polymeric material,such as Lexan™ or any other suitable polymeric material. The upper andlower U-shaped frames 126, 128 are preferably made of steel rod, tube orother structure and the hooks 132, 134 are preferably also made of acompatible metallic material, preferably steel, and connected to theupper and lower U-shaped frames 126, 128 via welding, riveting or othersuitable means. The hook 134′ is made of spring steel or a suitableresilient material, as discussed above. The carrier sled 136, 136′ ispreferably made of a compatible metallic material, such as steel.

Utilizing the U-Bar suspension assembly 120, 120′ allows quick and easyinstallation in a consistent and repeatable manner relative to thepiling strands 12 of the sensors such as a strain gauge 124 andaccelerometer assembly 122 while maintaining a precise alignment andpositioning so that the accelerometer is orthogonal to a length of andwithin the core of the piling being formed, and the strain gauge 124extends axially, parallel to a length of and within the core of thepiling being formed. The U-bar assembly 120, 120′ is designed to providefor accurate mechanical registration of the gauge/sensor assembly on thesled 136 with the precisely located strands 12 in the piling form 14based on the location of the strands in order to ensure accurate andrepeatable placement of the gauge/sensor assembly, preferably in thecenter of the piling core.

FIG. 27 shows the positioning of the sensors 16 in the piling 10, aswell as the positioning of the antenna/radio assembly 60 and the antennaassembly 62. A single cable 170 extends between the tip sensors 16 andthe housing 61 for the transmission of data within the pile 10. Thesensors 16 are positioned preferably using the U-bar suspension assembly120, 120′ or any other suitable system to hold them in position betweenthe strands 12. By locating an antenna on opposing sides, it is alwayspossible to receive an RF signal from the pile, regardless of itsorientation.

FIG. 28 shows an alternate preferred arrangement of the sensor andsignal transmission system of the piling 10. A tip sensor package 16 b,which preferably includes an accelerometer assembly 122 and a straingauge 124, is located near the tip. At least one antenna 18 is locatednear the piling top, and an additional sensor package 16 a is preferablyalso located at or near the piling top. Preferred locations for the topand tip sensor packages 16 a, 16 b based on the piling size are alsoindicated. Preferably, the tip sensor package 16 b includes anon-volatile memory (NVRAM) for storing pile life history data, gaugecalibration data and other pile drive related data. This can be includedin the electronics module 159 or separately positioned.

The sensor packages 16 a, 16 b preferably include one of the U-barsuspension assemblies 120, 120′ with provisions for holding theaccelerometer assembly 122 and a strain gauge 124, which must bepositioned within the pile core, as well as the conditioning electronics159. The U-bar suspension assemblies 120, 120′ provide for quicker andeasier mounting of the sensors 16 a, 16 b, reducing assembly time andcosts.

In the preferred embodiment shown in FIG. 28, a tube 230, preferablymade of plastic material, extends between the tip sensor package 16 band the electronics module housing 61 of the antenna/radio assembly 60.The cable or wire 231 that extends between the tip sensor package 16 band the electronics module housing 61 is run through the tube 230, asshown in FIG. 29.

FIG. 30 shows a schematic view of this arrangement without the pile 10.An enlarged area or reservoir 233 for an excess amount of the wire orcable 231 is located near or at the tip sensor package 16 b. Theenlarged area or reservoir 233 can also be in the form of a bulb at theend of the tube 230, and is sealed to the wire or cable 231 that extendstoward the sensor package 16 b. This allows excess wire or cable 231 tobe drawn up from the chamber 233 for splicing in the event that the topof the pile 10 is cut off after installation so that the accelerometerand strain gauge 122, 124 including any other sensors and/or NVRAMlocated at the tip sensor 16 b can still be connected to a networkedmonitoring node for continued monitoring, as explained in further detailbelow. Additionally, all of the data stored in the memory located withthe conditioning electronics 159 for the sensors in the tip sensorpackage 16 b can be accessed.

Preferably, the tube 230 is tied loosely to the strands 12 down the pile10 using cable ties or other suitable connectors, as shown in FIGS. 28and 29, such that the tube 230 is generally held in place but notpinched and the cable or wire 231 is slidable within the tube 230.

Referring to FIG. 31, a schematic view of a pile 10 showing the commondata backbone in the form of the cable 170 or 231 is shown. Inaccordance with a preferred system overview of one embodiment of theinvention, a wireless coupling arrangement via fiber optic, RF, magneticor a hard connection is located at the tips and tops of stacked (orspliced) vertical concrete piles, indicated as transceiver modules 260.This can be provided as an embedded receiver module at the tip of eachpile and an embedded transmitter module at the top, and a commonconnection via a hard-wired link or back-bone to move data from the tipto the top of a pile in a pass-through mode. Alternatively, thetransceivers 260 can provide bi-directional data, depending on theparticular application.

Using this arrangement, data can be relayed and transmitted formonitoring from a below grade pile or spliced through a pile driven ontop of it. This allows the collection of information (data) from thevarious embedded sensing modules in the pile also commonly connected tothe hard-wired back-bone. Preferably, a method to discern where thetransmitted data originated is provided, for example, in the manner ofnetworked nodes.

Additionally, according to the invention, power can be coupled betweenstructures using a special provision of the same interface. This wouldprovide an automatic override of the internal power source should itfail to provide sufficient operating currents. Due to the (sometimesvery remote) operating locations, the power source to all structurescould also include solar energy obtained from the use of solar panels.

Optionally, it is possible to provide an auxiliary back-up connectionport that allows connection of an auxiliary power source, such as abattery in the event of an internal power source failure. External plugsor connections for direct readout of the data from the accelerometers,strain gauges, temperature sensors, and any other sensors can also beprovided through the hard-wired backbone embedded in the concretestructure in the event of a failure of an internal data logger, signalconditioner or transmitter so that the data from the sensors and gaugesin the concrete structure could still be collected in the event of apartial system failure.

Central sensor data multiplexing and control including radio interfaceelectronics are preferably provided in the housing 61 or in anotherhousing located within the piling, preferably having an access coverlocated at the piling surface.

A piling I.D., which preferably corresponds to the radio address or MAC(media access control) address for the transmitter, is stored in thememory along with the date of manufacture, the date of calibration andsensor details, sensor configurations, gain, offset, gauge factor,sensitivity, lot number, serial number, vendor, etc, along with dataverifying system QC. This initial information is preferably stored inthe non-volatile memory located with the tip gauge conditioningelectronics and is further augmented during the piling manufacture at acasting yard by adding information about the pile casting process, suchas casting yard, inspector name/number, date of casting, location ofpiling at casting, concrete modules, concrete specific weight, pilinglength, diameter or other geometry, temperature profiles (as explainedin detail below) and/or strain pre-load, which is recorded in the memoryfor a later use. Any casting data or other history regarding the formingof the piling can also be recorded so that it will be available later toassist in the driving process. The memory is preferably accessible bythe pile foreman to test and/or check the radio prior to and followingcasting in order to allow QC and any necessary repair prior to shippingand/or driving the piling. The casting yard inspector may also entercritical inspection parameter to be accessed and used during driving ofthe pile.

All of the data from the memory can be accessed by radio frequencytransmission from the piling using one of the antenna assemblies 60, 62or other types of the antenna assemblies noted above that are located onthe pile.

Once at an installation location, it is also possible to log informationin the memory with respect to a GPS location of the piling at the timeof driving, if available. This can be linked to a known soil propertymap in order to use the drive data to verify and/or determine soilproperties (with the driven pile functioning in the role of a soilprobe) and/or to modify the driving process.

The strain and force data gathered by the strain gauge(s) 124 andaccelerometer 122 during driving of the piling can be RF transmitted byone of the antenna assemblies 60, 62 for monitoring dynamically duringpile driving throughout the driving process. Critical absolute internalstrain information can thus be provided during the drive versus theprior known method of external monitoring of relative strain duringdriving. Specifically, the invention allows monitoring of the actualabsolute strain and using that information to ensure that driving forcesdo not exceed a level that would produce an undesirable tensioncondition in the piling. This absolute compression and tension stressinformation is preferably used to provide real time feedback to thehammer or crane operator in order to selectively control hammer energyand optimize the driving process. This information can also be used toprevent overdriving and subsequent pile failure by reporting andproviding feedback of the absolute allowable strain readings and ranges.

The inspector, date of drive, date of re-strike, if any, as well as themaximum stress can also be recorded in the memory. This data is thenavailable and trackable with each piling, and can be uniquely timestamped and tracked in the memory in a similar manner to an activeread/writable RF I.D. tag which can receive and store data as well astransmit data. Additionally, the drive inspector, civil engineeringinspector as well as the pile driving crane operator may be able toaccess the data in the sensor unit electronics memory during the drivein order to check or verify information with respect to the piling andits history. All of this piling history data is linked as a header tothe actual drive data and can be transmitted along with the drive datainto a piling database for further lifecycle and/or long termmonitoring, QA/QC traceability and accountability purposes.Additionally, this data can be used in connection with future analysisand comparisons to predict faults or failures.

Thus, the entire life cycle of the pile is captured in the non-volatilememory and can be accessed via RF transmission utilizing at least one ofthe antenna assemblies 60, 62. Additionally, in the case of antennafailure, the housing cover 64 can be accessed from the surface of thepiling 10, if necessary, in order to provide a manual electronicconnection and/or to replace the battery or electronics module used todrive the sensor unit electronics.

The memory is preferably in the form of a non-volatile RAM, EEPROM, orother writable optic or magnetic media, and is preferably accessed andcontrolled by a controller. It is also possible that the memory is anexpanded memory module used in connection with a known RF I.D. module.Preferably, the sensor unit electronics include a non-volatile memorywhich can capture data about the sensors as well as other informationabout the piling being formed. This is utilized in connection with thelife cycle tracking of the piling and its related data.

According to the invention, it is also possible to check the concretestrength and readiness through a temperature or curing profile withinthe concrete structure. Several standards detail this process (ASTM C1074). Temperature cure profiles can also be saved in the sensor unitelectronics memory by providing temperature sensors at the core of thepile as well as at the outer surface. Assuming that the thermal curingtemperature flux lines only vary radially outwardly from the core of thepile and remain fairly constant at the same point along the length ofthe pile, this data can be accurately tracked using the core and surfacetemperature sensors in order to determine a differential temperaturegradient in the pile to determine when the concrete reaches useablestrength.

Software may also be used to collect information from the sensoryelectronics and data loggers for presentation to users based on variousestablished roles such as casting foreman, yard inspector, driveinspector, crane operator, etc. The system is preferably configurable byone role in support of another. For example, the civil engineeringinspector may configure the system to flag warnings to the pile drivinginspector when specific operational ranges (strain, force, capacity,etc.) are exceeded. This may be applied to the crane operator or otherusers in order to ensure that specific driving criteria are met or thaterrors are flagged. The system can also track, count and transmit blowsbased on a criteria threshold.

Additionally, by positioning gauges at both the top and tip of the pile10 at a known distance, wave speed anomalies can be detected and usedfor comparison against certain pre-defined problematic conditions, suchas excessive strain, wave reflections caused by material discontinuitiessuch as a cracked pile, etc. using associated data signatures. When suchanomalies are detected or a potential match of anomaly data occurs, theoperator can be notified.

In a preferred embodiment, the accelerometer is either AC coupled or DCbias servo controlled to nullify the zero shift effect commonly found inpiezoelectric accelerometers. In the application of the preset inventionfor a piezoelectric (PE) accelerometer, the following application uniqueconditions are known:

The pile always starts out at velocity equal to zero.

The event being measured has a total cycle time of less than 200 msec.

The pile always returns to velocity equal to zero.

Because prior to and after the event being measured the velocity isequal to zero, and the event being measured occurs in a predeterminedand known time interval, AC coupling or the use of a fixed DC biascontrol using a servo control feedback for the conditioned accelerometersignal prior to data capture works around the zero-shift effect (orerror) common to PE accelerometers. This provides for better qualityaccelerometer data.

Utilizing the present invention, the entire history of a piling alongwith drive data can be monitored and captured. While the presentinvention specifically references accelerometer and strain gauge databeing captured during the drive, these are only preferred data types,and other types of sensors could also be used to capture and provideother types of data, such as a tip temperature sensor capturingtemperatures during the drive, or tip and top temperature sensors beingutilized to track a temperature gradient of the pile. Other types ofsensors could also be used.

While preferably long-life batteries are utilized in connection with thesensor unit electronics and memory, it is also possible to provide otherpower sources, such as vibration induced charge, solar power or othermeans. Additionally, access can be provided for attaching an externalpower source or replacing the internal power source.

According to the invention, it is also possible to allow the centralsensor data multiplexing and control including radio interfaceelectronics to be recovered by removing the housing cover 64. However,the sensor gauges would remain embedded and non-recoverable in thesystem. This would further reduce costs of the system by providing ameans of recovery a portion of the system for re-use.

Referring now to FIG. 32, in the case where the top of the pile 10 isnot cut-off, according to the invention the pile 10 is reconfigured forlong-term monitoring by removing the radio module from the electronicsmodule housing 61 of the antenna/radio assembly 60. A replacement andexternally powered networked monitoring node 314′ is then installed inthe housing 61 and connected to any available tip/top gauge cables orwires 231.

Referring now to FIG. 33, the pile 10 is shown after being driven, withthe top of the pile removed to a cut-off elevation based on theapplication requirements. In order to provide further monitoringthroughout the life cycle of the pile 10 and its subsequent make-up of astructure or foundation and to be able to access information in thememory located with the tip sensor package 16 b, the wire or cable 231can be pulled up from the reservoir 233 after the pile top is cut offand can then be spliced to a connector or cable that is connected to anetworked monitoring node 314, which can be embedded in a cappingstructure or otherwise located in proximity to the pile 10. This can bedone by a site technician. Accordingly, if the pile 10 is driven and thetop is cut off, and regardless of where this occurs below the top gauges16 a, there will always be a cross section of the tube 230 containingthe cable 231 exposed, as shown in FIG. 33.

Referring now to FIGS. 34A to 34C and 35, life cycle monitoring of thepilings according to the present invention is provided. This is done byretrofitting the individual piling antenna/radio assembly 60 with anetworked monitoring node capability. This provides a method forestablishing a powered local area network of select sensor-enabledpilings 10 and other sensors. These retrofitted nodes or dataports canbe located in the electronics module housing 61 prior to casting theconcrete cap 350, as shown in FIG. 35, and include a mechanism forself-configuring all of the connected piling nodes in the piles andconcrete structures that make up the transportation/building foundationand superstructure. The nodes or dataports are preferably interfacedusing a typical network protocol. Additionally, power is distributed bythe system to all of the gauges/sensors being monitored. Alternatively,the power distribution and networking functionality can be combined.

According to the invention, construction personnel will either replaceor augment the existing piling data ports located in the electronicsmodule housing 61 with a wired network that provides power and a wiredconnection for data transfer. The nodes that are added to this networkpreferably self configure and report up either in a peer-to-peer ormaster-host configuration. The network and/or wiring provides redundancyand addressability that ensures at least a subset of the connected pilesare available and/or accessible.

These newly networked pilings 10 making up a foundation can be connectedto a larger network or telemetry uplink such as GPRS, wired broadband,PowerLine networking, etc. 312, as shown in FIG. 35.

Historical life information concerning each pile 10 (including thedynamic installation details/results) will be logically transferred fromthe piles 10 and the tip sensor package 16 b now providing long termmonitoring.

All uploaded telemetry information from the drive and for the long termmonitoring of the pile 10 will be kept at a remote central repositoryfor review, monitoring, and reporting.

The system also provides a means of retaining the unique addressinginformation of a given radio, preferably by logically linking it to thesensor address ID, or through other means of synching or mapping theradio ID being replaced with the backbone ID of the replacing networkedmonitoring node 314.

The current piling sensor(s) 122, 124 to networked monitoring node 314connectivity is accomplished using low power differential signaling forpilings 10. While more tolerant to radio and materials interference, adigital signaling architecture would better eliminate any chances ofinterference and decouple the Radio/Monitoring modules from thetransducer transfer function. According to the invention, a digital busarchitecture will be utilized for all sensors used in the system. Inthis configuration:

-   -   Sensor details and calibration information are kept at the tip        sensor's conditioning electronics, with the digital bus        providing a means of communicating sensor calibration and sensor        data and all NVRAM contents;    -   A shared bus is used allowing multiple gauges and various        uniquely identified gauge types to share the same physical wired        backbone;    -   A high speed and power efficient bus protocol is used to address        the volume of data from each of the gauges:    -   A smart plug-and-play system is used to allow multiple gauge        configurations to be used, automatically identifying and self        configuring based on the gauges present;    -   In the event that the Radio/Monitoring module 60 must be        removed, the configuration/calibration of the gauges and life        history of the pile 10 is retained or mirrored by electronics        (such as a NVRAM) provided with the tip sensor 16 b electronics        for continued use by the replacement networked monitoring module        314.

The invention provides long term monitoring capability through the tipgauge data as well as data stored in the conditioning electronics NVRAM,regardless of the final pile configuration. In addition to the networkedmonitoring nodes 314 encapsulated in the cap 350, strain gauges andother sensors can also be located in the cap 350 and connected withadditional network nodes for cap gauges and sensors. This can beconnected with the gateway 312 so that cap data can be captured andtransmitted along with pile data. Further monitoring capabilities, forexample for monitoring additional structures, such as a pier or aroadbed located on the cap 350 shown in FIG. 35 can also be provided.These additional monitoring capabilities can be carried out by providingnodes with self adapting network capabilities. Thus, monitoring of allof the elements in a given structure can be carried out through the useof a stackable network topology built upon the basic pile monitoringsystem described in detail herein. This provides a system or structurewhere the pile sensors are wired along with other sensors into a cap,which is then wired along with other sensors into a pier, which is thenwired along with other sensors into a roadbed, ultimately providing datafor a partially or completely integrated structure (including one ormore of the noted components and/or other structural components) via atelemetry uplink.

Referring now to FIG. 36, an improved means for determining pilepenetration and ultimately the load bearing capacity of the pilingaccording to the invention is provided. The current means of determiningpile penetration (and ultimately capacity) of a concrete pile involvemanually putting markings on one side of the pile and an inspector whois responsible for counting the pile hammer blows (via a saximeter) andnoting the movement/penetration of these marks moving past an elevationreference marker. This process requires effort and personnel involvementthroughout the course of the drive. The present invention canautomatically and accurately count the hammer blows through gauge 122,124 excitation beyond a set threshold within the pile 10 internally orfrom signals received and interpreted by a tracking/monitoring device,such as a Pile Workstation (SPW) 320, which is a centralized systemcontroller that collects real time drive data from the sensors andgauges within the piles 10, interfaces with the height sensing pilepenetration system, described below, tracks blow counts (internally orexternally) and calculates and synchronizes blows per displacement withthe dynamic data collected during the pile drive to communicateinformation to the inspector in real time for controlling the drive aswell as providing real time pile load capacity data.

Tracking the displacement of the pile 10 according to the invention canbe carried out by one of several methods.

In a first method, a laser lidar “time of flight” and triangulationconcept is utilized coupled to a SPW 320. In this configuration, a laserlidar system 322 is first projected level to a reference elevationrelative to a vertical standing pile 10 to determine the adjacent sideof a right triangle A. The lidar system 322 is then pivoted up the faceof a vertical standing pile to a reference point 324 near the top of thepile 10 to determine the corresponding hypotenuse C of the righttriangle. The vertical height of the pile 10 above the referenceelevation is based on the distance B from the reference elevation up tothe reference point 324 located at a known distance X down from the top.Knowing the overall length L of the pile 10, as well as the dynamicallycalculated distance B and the distance X, the pile penetration P belowthe reference elevation can easily be calculated. The change in heightcan easily be determined based on the change in C.

The reference marker 324 at the top of the pile 10 would be constructedto facilitate automatic vertical tracking in the case of a verticallystanding pile and self alignment adjustment by the pivoting lidar head(via a motorized servo control system). A retro-reflective line ormirrored object can be utilized.

The lidar system 322 would continually compensate by locking on thereference marker 324 for the downward movement of the reference markertarget as the pile is being driven. The system dynamically provides rawreal time calculated pile height B or calculated pile penetration P datato a tracking monitoring device SPW 320. This used in conjunction withthe blow count being derived by the internal gauge system would be usedto calculate/record/track the blows/foot, providing for fully automatedtracking.

Alternatively, the lidar is projected to a common point at the top ofthe pile 10, which includes the possibility of putting the referencemarker on the hammer or cap, after having obtained a distance orthogonalto the standing pile (length) surface at the reference elevation. Thepile penetration is continuously determined by subtracting the measuredpile height above the reference elevation (determined fromtriangulation) from overall pile length L. A vertically repositioningscanning system (in the case of vertically extending piles) ispreferably used to account for a continually shortening height. It isalso possible for the system be able to sweep the pile from top tobottom to determine the angle of the standing pile and project to apoint non-orthagonal to the pile at the reference elevation and to thenuse known trigonometric techniques to determine the necessary data Thiscan be coupled with SPW 320 to replace the inspector's need tophysically collect pile drive data. The SPW 320 counts or keeps track ofblows and synchronizes this data relative to pile penetration data tothen calculate the blows per displacement based on the calculated pilepenetration P.

Alternatively, an IR based sensor time of flight camera could be used todetect and reference the centroid of a predetermined point on the hammeror the pile, such as the pile cushion, using thermal imaging.Additionally, a pivoting camera system using 3D image sensing andpattern recognition could also be used as a target identifier to replacethe lidar head referenced above.

A second method of determining the penetration depth of the driven pileis through the use of barometric altimeters, as shown in FIG. 37. Twobarometric altimeters 340, 342 provide two measurements each: barometricpressure and altitude. In general, when measuring altitude, barometricaltimeters can be used over short periods after calibration, and areconstantly recalibrated to zero-out the barometric pressure changescaused by changing weather patterns. Some systems do this by gettingaltitude information from GPS satellites, knowing the difference isbarometric pressure. According to the invention, a digital barometricaltimeter 340 is mounted on the piling 10 or on the hammer or cap (withstand alone communication), and is preferably removably mounted at theelectronic module housing 61 and interfaces with one of the radio'sdigital channels. The height B is then determined by differentiallycomparing the transmitted data from the pile or hammer mounted altimeter340 with another barometric altimeter 342 mounted down at the fixedreference elevation (or other known elevation), such as the previouspile depth marker string. Measuring the outputs of the altimeters 340,342 differentially effectively removes the common-mode or absolutebarometric pressure from the equation, and provides a pure differentiallocalized altitude or relative barometric pressure reading during thecourse of the drive. Raw data is preferably collected by a monitoringdevice 344 that receives the signals from both altimeters 340, 342 in afashion similar to that described above. The height is supplied by thealtimeters or calculated in the SPW 320. Preferably, the altimeters 340,342 are calibrated relative to each other at the same elevation prior touse to zero out tolerance errors. The communication from the altimeters340, 342 can be to the monitoring device 344 using wireless or wiredconnections and/or can be directly with SPW 320 using the radio/antennaassembly 60 for the pile mounted altimeter 340 and a separate wired orwireless connection from the reference elevation altimeter 342,depending on the location. The bottom altimeter 342 can be located awayfrom the pile 10 at the job site as long as it is maintained at thereference elevation.

While these approaches assume piles are driven co-linear with gravity,corrections and adjustments can be made through the use of aninclinometer and triangulation for the case of angled piles. It iscommon for piles carrying high lateral loads to be driven at an angle ofup to 45° (batter piles). In this instance, an inclinometer is used todetermine compensation angles and the penetration depth is calculatedusing known trigonometric techniques.

While the preferred embodiments of the invention have been described indetail, the invention is not limited to the specific embodimentsdescribed above, which should be considered as merely exemplary. Furthermodifications and extensions of the present invention may be developed,and all such modifications are deemed to be within the scope of thepresent invention as defined by the appended claims.

1. A method of monitoring pilings, comprising: inserting a sensorpackage between strands or reinforcements in a piling form to positionsensors in a core area of a piling; connecting a radio module to thepiling, the radio module being in communication with the sensor package;casting the piling; determining the strain pre-load and recording it forlater use; driving the piling and obtaining data from the sensor packageduring driving; at least one of monitoring the data obtained from thesensor package during driving and monitoring and using the data duringthe driving to adjust driving parameters for the pile; and usingabsolute internal strain information from the data obtained from thesensor package located inside the piling core to maximize drivingefficiency in real time during driving of the piling.
 2. The method ofclaim 1, further comprising: monitoring absolute internal straininformation to ensure that driving forces do not exceed a level thatwould produce a damaging tension stress condition in the piling.
 3. Themethod of claim 1, further comprising: monitoring absolute internalstrain information for changes in pre-load during driving; and usingthis information to predict piling failure.
 4. The method of claim 1,further comprising: inserting the sensor package at a tip of the pilingand inserting a second sensor package at a top of the piling.
 5. Themethod of claim 1, further comprising: detecting wave speed anomaliesusing the data and a known distance between the sensors in the piling;and comparing the wave speed anomalies against pre-defined conditionsfor failure detection.
 6. The method of claim 1, further comprising:storing the data obtained from the sensor package in a memory.
 7. Themethod of claim 1, further comprising: transmitting the data obtained toa piling history database for further lifecycle and long termmonitoring.
 8. The method of claim 7, further comprising: cutting off atop of the piling; and pulling excess wire or cable located inside ahollow tube from a wire reservoir in proximity to a piling tip in orderto connect the sensor package located at a tip of the piling to thenetworked monitoring node.
 9. The method of claim 1, further comprising:retrofitting the piling installing a networked monitoring node that isconnected to the sensor package; retaining unique addressing informationof a given piling, by logically linking a sensor package address ID; andconnecting the node to an external gateway for data transmission forlong term monitoring.
 10. A method of long-term monitoring for pilings,comprising: forming a cast concrete piling with a sensor package locatedin a core area of the piling; determining a strain pre-load andrecording it for later use; driving the piling and obtaining data fromthe sensor package during driving; retrofitting the piling by installinga networked monitoring node that is connected to the sensor package;retaining unique addressing information of a given piling, by logicallylinking a sensor package address ID; and connecting the node to anexternal gateway for data transmission for long term monitoring.
 11. Themethod of claim 10, further comprising: storing pile data in a memorylocated in the piling.
 12. The method of claim 11, further comprising:for a pile having the top cut off after driving, pulling excess wire orcable located inside a hollow tube from a wire reservoir in proximity toa tip wire or cable reservoir in order to connect a tip sensor packageto the networked monitoring node.
 13. The method of claim 10, furthercomprising: providing a GPS at the pile; obtaining a location for thepile; and obtaining soil properties for the location.
 14. The method ofclaim 10, further comprising: providing a re-writable memory in thepiling; and storing and updating data in the re-writable memory.
 15. Asuspension assembly for positioning at least one sensor between strandsin a concrete structure, comprising: first and second U-shaped framesconnected to one another; at least one strand engaging member located oneach of the U-shaped frames facing away from one another and adapted toengage opposing reinforcement strands or bars of a concrete structure; aslidable carrier attached to the frames for supporting at least onegauge; the first and second U-shaped frames are spring biased away fromone another; and centering springs extend between the slidable carrierand the frame for movably sliding the slidable carrier to a centeredposition on the U-shaped frames, the slidable carrier includingprovisions for attaching sensors.
 16. The suspension assembly of claim15, wherein at least one of the strand engaging members is formed of aspring material.
 17. The suspension assembly of claim 15, furthercomprising: a strain gauge connected to the slidable carrier.
 18. Thesuspension assembly of claim 15, further comprising: an accelerometerconnected to the slidable carrier.
 19. A suspension assembly forpositioning at least one sensor between strands in a concrete structure,comprising: first and second U-shaped frames connected to one another;at least one strand engaging member located on each of the U-shapedframes facing away from one another and adapted to engage opposingreinforcement strands or bars of a concrete structure, a slidablecarrier attached to the frames for supporting at least one gauge; afirst opening with at least two opposing V-shaped side walls forregistration with a first sensor housing located in the slidable carrieror a mounting plate connected thereto; and a second opening defined inthe slidable carrier or the mounting plate connected thereto for asecond sensor.